The mouth

The mouth is the starting place for the digestive system and thus the point at which ingestion occurs.  It serves to mechanically break food into smaller pieces by biting and chewing. The mouth has four (4) types of teeth:

Incisors: chisel shaped teeth in the front of the mouth and serves in biting. Total of 8 in the adult mouth.

Canines: Sharpe and pointed teeth located just outside the incisors and serves in tearing of food. Total of 4 in the adult mouth.

Premolars and molars: Flattened and rigid for the grinding of food. Total of 8 premolars and 12 molars in the adult mouth.

The structure of the tooth

There are 2 types of dentitions in humans:  the milk dentition and the permanent dentition.

Milk dentition

These are found in the young and are eventually lost.

Permanent dentition

These are the permanent set of teeth found in adults. These teeth replace the milk dentition and total thirty-two (32) in all.

Food in the mouth is moistened with saliva. The saliva is secreted by the salivary glands and contains the enzyme amylase which breaks down starches into to the disaccharide maltose. The tongue is responsible for the rolling of this moistened crushed food into tiny balls called the bolus.